Atrial appendage blood filtration systems

ABSTRACT

Instrumentation for percutaneous delivery of blood filtration devices to atrial appendages includes a curved access sheath and a delivery tube. A compressed filter device attached to a tether wire is loaded in the delivery tube. The access sheath and the delivery tube can be mechanically locked and moved together to place the device in a suitable deployment position. The device is deployed by expelling it from the delivery tube either by retracting the delivery tube over the tether wire, or by moving the tether wire forward through the delivery tube. A filter membrane in the deployed device extends across the appendage ostium to filter blood flow through the ostium. The filter membrane is configured to present a flat surface to atrial blood flow past the ostium.

This application is a continuation of U.S. application Ser. No.14/806,446, filed Jul. 22, 2015 which is a continuation of U.S.application Ser. No. 10/351,736, filed Jan. 24, 2003, now abandoned,which claims the benefit of U.S. provisional application No. 60/351,898,filed Jan. 25, 2002, U.S. provisional application No. 60/379,921, filedMay 10, 2002, U.S. provisional application No. 60/417,110, filed Oct. 8,2002, and U.S. provisional application No. 60/403,720, filed Aug. 14,2002, all of which are is hereby incorporated by reference in theirentireties herein.

BACKGROUND OF THE INVENTION

The invention relates to filtration of cardiac blood flow between anatrial appendage and its associated atrium. The blood filtrationprevents the dispersal of thrombi, which may be formed in the atrialappendage, into the body's blood circulation system. In particular theinvention relates to implant filter devices, and apparatus for thepercutaneous delivery and implantation of such devices in the heart.

Structural heart disease or other cardiac conditions in a patient canresult in atrial fibrillation, which in turn causes blood to pool orstagnate in the patient's atrial appendage. Thrombi (i.e., blood clots)are prone to form in the atrial appendages with stagnant blood. Theblood clots may subsequently break off and migrate to the brain leadingto stroke, or to other parts of the body causing loss of circulation tothe affected organ. The left atrial appendage (LAA), which isanatomically disposed on top of the left atrium, happens to be aparticularly likely site for harmful blood clot formation.Thromboembolic events such as strokes are frequently traced to bloodclots from the LAA.

The risk of stroke in patients with atrial fibrillation may be reducedby drug therapy, for example, by using blood thinners such as Coumadin.However, not all patients cannot tolerate or handle the blood thinningdrugs effectively. Alternative methods for reducing the risk of strokeinvolve surgery to remove or obliterate the LAA. Other proposed methodsinclude using mechanical devices to occlude the atrial appendage openingand thereby stop blood flow from the atrial appendage into itsassociated atrium.

Another prophylactic method for avoiding strokes or other thromboembolicevents caused by blood clots formed in atrial appendages involvesfiltering harmful emboli from the blood flowing out of the atrialappendages. Co-pending and co-owned U.S. patent application Ser. No.09/428,008, U.S. patent application Ser. No. 09/614,091, U.S. patentapplication Ser. No. 09/642,291, U.S. patent application Ser. No.09/697,628, U.S. patent application Ser. No. 09/932,512, U.S. patentapplication Ser. No. 09/960,749, U.S. patent application Ser. No.10/094,730, U.S. patent application Ser. No. 10/198,261, and U.S. patentapplication Ser. No. 10/200,565, all of which are hereby incorporated byreference in their entireties herein, describe filtering devices whichmay be implanted in an atrial appendage to filter the blood flowing outof the atrial appendage. The devices may be delivered percutaneously tothe heart through the body's blood vessels using common cardiaccatheterization methods. These catheterization procedures often involvefirst deploying an access system to position an access sheath through apatient's vascular system to the interior locations in the patient'sheart. The access sheath provides a passageway through which implantdevices are passed from outside the patient's body to interior locationsin the heart. Delivery of the devices to the LAA may involve transseptalcatheterization procedures, in which access to the left atrium is gainedfrom the right atrium by puncturing the intervening septum. One or moreindependent delivery systems may be used to deliver the devices throughthe access sheath.

U.S. patent application Ser. No. 09/932,512, U.S. patent applicationSer. No. 10/094,730, and U.S. patent application Ser. No. 10/200,565,disclose expandable implant devices which are small and which can bedelivered percutaneously by catheters to the atrial appendages. Theeffectiveness or success of medical procedures using the implant devicesmay depend on the proper deployment and retention of the devices in asuitable orientation in the atrial appendages. U.S. patent applicationSer. No. 09/960,749 discloses a catheter apparatus having positionguides. U.S. patent application Ser. No. 10/198,260 discloses a catheterapparatus having a device tether, which allows a deployed device to beretrieved for repositioning as necessary.

Consideration is now being given to improving implant devices and toimproving catheterization apparatus including access and deliverysystems for the percutaneous delivery of such devices throughgeometrically complex vascular paths leading, for example, to the leftatrial appendage.

SUMMARY OF THE INVENTION

The invention provides instrumentation for percutaneously implantingfilter devices in atrial appendages to filter blood flowing between theatrial appendages and associated atrial chambers. The filter devices aredesigned to prevent dispersal of blood clots formed in the atrialappendages into the body's blood circulation system.

The filter devices are self-expanding elastic or compressible framesmade from chicken wire-like mesh. The wire frames are made ofshape-memory alloy materials such as nitinol. A typical device at itsnatural or expanded size may be about an inch in diameter and about aninch long. The wire frames may have a generally cylindrical or conicalshape with a closed end. A blood-permeable filter membrane covers theclosed end. The filter-membrane covered closed end extends across theostium of a subject atrial appendage in which a device is used. In oneembodiment, the filter membrane is made of a polyester weave or knithaving a nominal hole size of about 125 um. The filter membrane filtersharmful-sized emboli from the blood flow between the appendage and theatrium.

The wire frame sides are shaped for an interference fit in the subjectatrial appendage in which the device is used. The closed end wiresections may be S-shaped and serve as resilient springs, which push orbias the cylindrical side portions of the wire frame outward.Additionally, tissue-engaging barbs are disposed on the wire frame toaid or encourage retention of the device at its implant location. Thewire frames have sockets or other fixtures for attaching a deliverytether wire or shaft. The attachment sockets are disposed aboutlongitudinal frame axis at or about the wire frames' closed ends. Thewire frames are suitably recessed to accommodate the attachment socketsso that closed ends of the devices (the supported filter membranes) havea substantially undulating or flat surface topography.

The filter devices may be percutaneously implanted in a patient's atrialappendage. Inventive device delivery systems and instrumentation may beused for the implant procedures. The instrumentation includes a curvedtubular access sheath. The implant procedures involve introducing theaccess sheath into the patient's blood vessels through a skin punctureand coursing it through a patient's vascular system to the interiorlocations in the patient's heart, for example, across the atrial septum.The coursed access sheath establishes a channel or passageway for devicedelivery to an atrial appendage through the patient's vasculature.

The distal portions of the access sheath are curved. The curvatures maybe simple or compound. The curvatures take into account the anatomicalgeometry of the heart and are designed to provide a passageway leadingdirectly to the subject atrial appendage. In an embodiment, the accesssheath is made from J-shape tubing, with a distal portion that has abend of about 90 degrees. In another embodiment, the access sheath ismade from similar J-shape tubing, the distal portion of which has afurther second bend away from the J-shape plane.

In a transseptal device implantation procedure the suitably curvedaccess sheath may be set up across the septum so that its distal end isdirected toward the subject LAA. Access sheath may be further advancedinto the LAA itself if so desired.

A device delivery system may be used to move a filter device through thepre-positioned access sheath. The delivery system includes a deliverycatheter tube that extends into a tubular implant sheath. The filterdevice that is to be implanted is attached to a tether wire or shaftpassing through the delivery catheter tube. The tether wire or shaft ismade from flexible wire material (e.g., nitinol). A threaded fixture atthe end of the tether wire may be used for device attachment. Theattached filter device is compressed to a narrow diameter size andconfined in the implant sheath extending from the delivery cathetertube.

The delivery catheter tube (with the device loaded in the implantsheath) is inserted into the pre-positioned access sheath leading to thesubject atrial appendage. The implant sheath is advanced through theaccess sheath to a suitable device deployment location. The deliverysystem and access sheath may include mechanical couplers or adapters tolock the delivery tube to the access sheath. When locked together, thedelivery catheter tube and the access sheath may be moved together, forexample, to place or orient implant sheath in the suitable devicedeployment location. The device is deployed by expelling it from theimplant sheath at a suitable location in or about the subject atrialappendage. On expulsion from the confining implant sheath the filterdevice self-expands to its useful size.

The delivery system may include remote actuators to expel or uncoverfilter devices for deployment. In one embodiment, a knob or handle isattached to the proximal end of the tether wire. The knob may bemanipulated to translate or turn the tether wire. The tether wire istranslated through the delivery tube to push the confined implant deviceout of the implant sheath. The tether wire diameter is selected toprovide sufficient rigidity for transmitting mechanical translation androtational forces to the attached implant device. Portions of the tetherwire close to the attached implant device have a reduced diameter toreduce the coupling stiffness of the tether wire to the attached implantdevice. This reduced coupling stiffness is advantageous in deploying thedevice in its natural unbiased state while it is still attached to thetether wire.

In another embodiment of the delivery system, additionally oralternatively, the delivery tube is partially retractable over thetether wire into a handle portion. A sliding actuator, which is attachedto the delivery tube, is disposed on the handle portion. The filterdevice may be expelled from the implant sheath by retracting deliverytube into the handle portion by activating the actuator on the handleportion. In either embodiment, distal portions of the tether wireadjoining the attached device may be encased in a flexible elastomericmaterial coil, which occupies the implant sheath lumen around the tetherwire. The flexible coil reduces any buckling tendencies, which a movingflexible tether wire may have. Next, the tether wire may be detached byunscrewing it from the deployed device by turning a knob attached to theproximal end the tether wire. The delivery system may include mechanicalfeatures or releasable stops to limit the translation or rotation of thetether wire. Use of the releasable stops limits the possibilities forinadvertent expulsion of the device from the implant sheath andinadvertent release or loosening of the device attachment.

Both the access sheath and the delivery system tubes have suitable valveassemblies attached to their proximal ends to prevent fluid leakageduring the device implantation procedure. The valve assemblies mayinclude ports for injection of fluids through the various tube lumens.For example, the delivery catheter tube may be attached to a large boreTuohy-Borst valve assembly. The Y-arm of the valve assembly may be usedfor intermittent or continuous fluid flushing and contrast injection orfor continuous blood monitoring during the implantation procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross sectional view of a heart illustrating theposition of the left atrial appendage relative to the chambers of theheart and some of the major blood vessels.

FIG. 2 is a side elevational view of an inventive delivery systemincluding a delivery catheter tube having an implant sheath attached toits distal end. The implant sheath contains an unexpanded filter deviceattached to a distal flex coil end of a tether wire passing through thedelivery tube lumen.

FIG. 3a is an enlarged cross sectional view of a distal section of thedelivery system of FIG. 2 with the distal flex coil end of a tether wireextending into the implant sheath in accordance with the principles ofthe invention.

FIG. 3b is a side elevational view of the implant sheath of FIG. 3acontaining an unexpanded filter device attached the distal flex coil endof the tether wire extending into the implant sheath in accordance withthe principles of the invention.

FIG. 3c is a side elevational view an unsheathed and expanded filterdevice attached to the distal flex coil end of the tether wire of FIG.3a in accordance with the principles of the invention.

FIGS. 4a and 4b respectively are a side elevational and across-sectional view of a flexible coil portion that encases the tetherwire in accordance with the principles of the invention. The inset FIG.4c is an enlarged view of a portion of FIG. 4b showing details of themechanical attachment of flexible coil portion and the encased tetherwire.

FIG. 5 is an enlarged cross sectional view of the proximal portion ofthe delivery system of FIG. 2.

FIGS. 6 and 7 respectively are a side elevational view and a plan viewof another catheter delivery system in accordance with the principles ofthe invention. The delivery system includes a delivery tube extendinginto a larger diameter implant sheath and a tether wire having a controlknob at its proximal end. The inset in FIG. 7 is an enlarged view ofsection B showing details of the mechanical attachment of flexible coilportion and the encased tether wire.

FIG. 8 is a side view of the components of a transseptal access systemincluding a sheath, a dilator, a Brochenbrough needle and an obturatorin accordance with the principles of the invention.

FIG. 9 is a plan view of an access system sheath in which the sheath tiphas a simple curvature in accordance with the principles of theinvention.

FIG. 10 is a plan view of an access system sheath in which the sheathtip has compound curvatures in accordance with the principles of theinvention.

FIG. 11a is a side elevation view of the sheath tip portions of theaccess system sheath of FIG. 10.

FIG. 11b is a rear elevation view of the access system sheath of FIG.10.

FIGS. 12a is a cross sectional view of a delivery system tube insertedin an access system sheath in accordance with the principles of thepresent invention. The delivery system tube is partially inserted in theaccess system sheath.

FIGS. 12b is a view similar to that of FIG. 12b illustrating thedelivery system tube inserted in and locked with the access systemsheath. In the locked position the distal tips of the two are aboutflush. Inset B is an enlarged view of the locking portions of thedelivery tube and the access system sheath.

FIG. 13a is a rear side elevational view of an expanded filter deviceshowing a filter membrane and portions of the expandable wire frame onwhich the filter membrane is supported in accordance with the principlesof the invention.

FIG. 13b is a partial side elevational view of the expanded wire framestructure of the filter device of FIG. 13 a.

FIG. 13c is an enlarged cross sectional view of the central portion B ofthe filter device of FIG. 13b illustrating the attachment of the filtermembrane to the wire frame structure in accordance with the principlesof the invention.

FIG. 13d is a cross sectional view of the expanded wire frame structureof FIG. 13b sectioned at plane A-A, illustrating barb elements suitablefor engaging atrial appendage wall tissue to secure the position of thedeployed device in an atrial appendage in accordance with the principlesof the invention.

FIG. 13e is a side elevational view of a solid preform used infabricating the expanded wire frame structure of FIG. 13b in accordancewith the principles of the invention.

FIG. 14a is a side elevational view of another expanded filter deviceshowing a filter membrane and portions of an expandable wire frame onwhich the filter membrane is supported in accordance with the principlesof the invention.

FIG. 14b is plan view of the proximal end of the device shown in FIG. 14a.

FIG. 15a is a side elevational view of the expanded wire frame structureof the device of FIG. 14a in accordance with the principles of theinvention.

FIG. 15b is an enlarged view of portion A of the wire frame of FIG. 15aillustrating the detailed configuration of the wire frame collar inaccordance with the principles of the invention.

FIG. 15c shows another side elevational view of the wire frame of FIG.15a , which has been rotated by about 15 degrees around the device'scylindrical axis.

FIG. 15d is an enlarged view of a barb-carrying portion C of the wireframe of FIG. 15c illustrating the disposition of a tissue-engaging barbin accordance with the principles of the invention.

FIG. 15e is an enlarged plan view of portion B of the wire frame of FIG.15c illustrating the details of the wire configuration in the wire framestructure.

FIGS. 15g and 15f are rear elevational and rear side elevational viewsof the wire frame of the filter device of FIG. 15 a.

FIGS. 16a and 16b respectively are a side elevational view and a planview of another access system in accordance with the principles of thepresent invention.

FIGS. 17a, 17b and 17c respectively are a side elevational view, a planview and a cross-sectional view of another delivery system tube inaccordance with the principles of the present invention.

FIGS. 18a and 18b are respectively are a side elevational view and aplan view of the delivery system tube of FIG. 17a and the access systemsheath of FIG. 16a in a locked position in accordance with theprinciples of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Devices for filtering or otherwise modifying blood flow between a leftatrial appendage (LAA) and its associated atrium may be implanted in theLAA. A catheter access sheath is percutaneously coursed through a bloodvessel leading to the heart to gain access to the LAA. A delivery systemis used to move the device through the access sheath into the LAA. Thedelivery system includes a shaft or wire to control movement of theimplant device.

Atrial fibrillation results in harmful clot formation primarily in theLAA. Therefore, it is anticipated that the invention will be mostly usedfor filtering blood flow from the LAA. However, it will be understoodthat the invention may also be used for the right atrial appendage andin general for device placement across any aperture in the body throughwhich blood flows.

The implant filter devices may have adjustable sizes. A compact ornarrow size is used for percutaneous device delivery to the atrialappendages, for example, by cardiac catheterization. The devices includesize-adjusting expansion mechanisms that allow the device size to beenlarged in situ to an expanded size. Alternatively, the devices mayhave self-expanding elastic structures. The devices may be held inposition in the atrial appendage by outward contact pressure exerted bythe outer structures of the enlarged device against the atrial appendagewalls. This outward pressure provides an interference-like fit of thedevice. The outward contact pressure may be a result of designedspringiness or elasticity of the device structure itself. Alternate oradditional mechanical means such as inflatable balloons enclosed withinthe filter device also may be used to generate the outward pressure.

In addition (or as an alternate) to the pressure generatedinterference-like fit, tissue-engaging anchors may be used to hold animplanted device in place. These anchors are generally disposed onexterior device surfaces and engage atrial appendage wall tissue whenthe device is deployed in an atrial appendage. The anchors may be pins,hooks, barbs, wires with a traumatic bulb tips or any other suitablestructures for engaging appendage wall tissue.

A variety of filter devices have been disclosed in U.S. patentapplication Ser. No. 09/428,008, U.S. patent application Ser. No.09/614,091, U.S. patent application Ser. No. 09/642,291, U.S. patentapplication Ser. No. 09/697,628, and U.S. patent application Ser. No.09/932,512, U.S. patent application Ser. No. 10/094,730, and U.S. patentapplication Ser. No. 10/200,565, all incorporated by reference herein.Other filter devices are disclosed herein, for example, expandabledevices 700 and 100. These devices are described herein with referenceto FIGS. 13a-13e , FIGS. 14a and b , and FIGS. 15a -15 g.

FIGS. 13a-13e show expandable filter device 700 having a filter membranecover 710. In FIG. 13a filter device 700 is shown in its natural orexpanded state. Filter membrane 710 is supported on an elastic wireframe 720, which has the general shape of a cylinder that is closed atone end. Filter membrane 710 covers the closed cylinder end and extendsalong the sides of the cylindrical wire frame 720. Filter device 700includes an insert or pin 715 having a socket 716 that is suitablyadapted for attaching filter device 700 to a device tether or shaft(e.g., tether wire 410, FIG. 3c ).

Device 700 may be expelled from the delivery tube at a suitabledeployment location in the atrial appendage where it (device 700) canexpand to its deployment state or natural size. When device 700 isdeployed in an atrial appendage, filter membrane 710 stretches across orcovers the atrial ostium and intercepts blood flowing in and out of theatrial appendage. Filter membrane 710 is made of blood-permeablematerial having fluid conductive holes or channels extending acrossmembrane 710. Filter membrane 710 may be fabricated from any suitablebiocompatible materials. These materials include, for example, ePFTE(e.g., Gortex®), polyester (e.g., Dacron®), PTFE (e.g., Teflon®),silicone, urethane, metal fibers, and other biocompatible polymers.

The hole sizes in the blood-permeable material may be chosen to besufficiently small so that harmful-size emboli are filtered out from theblood flow between the appendage and the atrium. Suitable hole sizes mayrange, for example, from about 50 to about 400 microns in diameter. Inone embodiment, filter membrane 710 is made of a polyester (e.g.,Dacron®) weave or knit having a nominal hole size of about 125 um. Theopen area of filter membrane 710 (i.e., the hole density) may beselected or tailored to provide adequate flow conductivity foremboli-free blood to pass through the atrial appendage ostium. Further,portions of filter membrane 710 may be coated or covered with ananticoagulant, such as heparin or another compound, or otherwise treatedso that the treated portions acquire antithrombogenic properties toinhibit the formation of hole-clogging blood clots.

FIG. 13b illustrates the structure of wire frame 720. Wire frame 720 hasa generally cylindrical structure that is closed at one end (right end).Wire frame 720 may be designed to have a lightweight open structure. Forexample, wire frame 720 may have an open structure that resembles thatof a chicken wire mesh. The wire sizes in wire frame 720 may be suitablychosen with consideration to the structural strength and elasticproperties of the fabrication material used (e.g., nitinol). Inpractice, the nitinol wires that are used in wire frame 720 may havetypical cross-sectional dimensions, which range from a few mils toseveral tens of mils (one mil.=one thousandth of an inch).

At the proximal end (right end) of wire frame 720, the frame wiresterminate in a cylindrical collar 722. Collar 722 is preferably locatedwithin the back plane of wire frame 720 (i.e., to the left of the planeof filter membrane 710, FIG. 13b ). The cylindrical side portions ofwire frame 720 are suitably shaped to engage atrial appendage walltissue and provide, for example, an interference fit in the atrialappendage in which filter device 700 is deployed. Other portions of wireframe 720 may be shaped to serve as resilient springs, which push orbias the cylindrical side portions of wire frame 720 radially outward.FIG. 13b shows, for example, S-shaped wire portions 723, serve asresilient springs to expand wire frame 720 to its natural orunconstrained size. S-shaped wire portions 723 emanate from wire collar722, and lie in the radial planes passing through passing through thecylindrical axis of wire frame 720. The S-shape of wire portions 723causes collar 722 (and insert 716) to be geometrically recessed relativeto the back plane of wire frame 720.

In addition, to geometrical shape features designed to retain or holddevice 700 in position inside an atrial appendage, wire frame 720 mayhave barbs 728 along its outer surface to engage atrial appendage walltissue. Barbs 728 may be distributed in any suitable pattern on theouter surface. FIGS. 13b, 13c and 13d show, for example, barbs 728 whichare equally spaced along a circumference of wire frame 720. Further, thediameter of cylindrical wire frame 720 may be varied by design toenhance device retention in an atrial appendage. For example, wire frame720 may have an outwardly distending ridge 724 that is designed tomechanically bias barbs 728 outward in an orientation suitable forengaging appendage wall tissue.

The diameter of cylindrical wire frame 720 also may be varied by designalong its longitudinal axis to obtain device shapes or structures thatreduce the likelihood of traumatic or undesirable tissue contact indevice use. For example, the distal wire ends (at left open end 726) offrame 720 may be turned radially inwards toward the longitudinal frameaxis. With the wire ends turned inward only smooth or rounded wireportions 727 of frame 720 may come in contact appendage walls. Thus,there is less likelihood of sharp or pointed wire ends coming in contactwith or puncturing atrial appendage walls or other tissue. Alternativelyor additionally, the frame wires may terminate in atraumatic tips atleft open end 726 of wire frame 720.

Filter device 700 may be fabricated with different-sized wire frames 720as necessary or appropriate for use in different sizes of atrialappendages. An exemplary wire frame at its natural expanded size may beabout an inch in diameter and about an inch long. As mentioned earlier,wire frame 720 may be made of suitable elastic material such as nitinol.Wire frame 720 may be made, for example, by machining a solid preformfrom a nitinol tube by laser cutting or other suitable machiningprocesses. Other fabrication methods such as braiding nitinol wires maybe alternatively used. FIG. 13e shows, for example, preform 730fabricated by laser cutting a nitinol tube. Wires 732 of preform 730terminate in cylindrical collar 722. Wires 732 may have attached stubs734 which when turned upwards form tissue-engaging barbs 728. Preform730 may be heat treated and shaped over a mandrel (not shown) tofabricate wire frame 720 having a desired geometrical shape, forexample, as shown in FIG. 13b . In a compressed state, wire frame 720returns to a narrow diameter tubular shape (not shown) similar to thatof preform 730 that is convenient for fitting device 700 in a narrowdiameter catheter or delivery tube for percutaneous delivery.

FIG. 13c is an enlarged cross sectional view of the central portion B offilter device 700 illustrating details of the co-assembly of filtermembrane 710, insert 715, and wire frame 720 in device 700. Portions offilter membrane 710 are held firmly between the inner surfaces ofcylindrical collar 722 and the outer cylindrical surfaces of insert 715,which is inserted in cylindrical collar 722. (Other portions of filtermembrane 710 may be tied (e.g., by suitable sutures or wire strands) orglued at one or more places to wire frame 720 to hold filter membrane710 against wire frame 720). Insert 715 has a threaded socket 716(threads not shown) to which a mating screw or threaded tether wire canbe attached. Insert 715 may be made of any suitable rigid materials thatcan be molded or machined to form threaded socket 716. Insert 715 may,for example, be made from hard plastics or metals such stainless steelor titanium. Insert 715 may have a diameter designed to provide asuitable interference fit in collar 722 to hold the filter deviceassembly together. Additionally or alternatively, mechanical means, forexample, cotter pin 717, may be used to hold insert 715 in place.Alternative mechanical methods such as riveting or the use of adhesivesor epoxies also may be used to hold insert 715 in place.

Device 700 as shown in FIGS. 13a and 13b has substantially the samecylindrical diameter over substantial portions of its cylindricallength. In other embodiments of the device, the cylindrical diameter mayvary by design. FIG. 14a shows an expandable filter device 100 whosecylindrical diameter decreases substantially over its (100) longitudinalaxis.

FIG. 14a shows filter device 100 in its expanded state. Filter device100 has a generally cone-like cylindrical shape that is closed at oneend. Filter device 100 includes a filter membrane 110 covering portionsof a wire frame 120 and includes other structures or features, which arethe same or similar to the corresponding structures in filter 700described above. For brevity, the description of device 100 herein isgenerally limited only to its features that may differ significantlyfrom the corresponding structures or features of device 700.

In its expanded state wire frame 120 has a generally cone-likecylindrical structure, which is closed at one end (right end). FIGS.15a-15f , illustrate the structure of exemplary wire frame 120, whichmay be made from a laser-cut solid nitinol tube preform. The varyingcylindrical diameter of wire frame 120 is chosen to give device 100 aconical shape in consideration of the typical shapes of atrialappendages in which the device is likely to be used.

At the right end of wire frame 120, wires 120 w that form wire frame 120terminate in cylindrical collar 122. FIG. 15b shows an enlarged view ofcollar 122 and portions of attached wires 120 w. Wires 120 w are shown,for example, as approaching and terminating at collar 122 at a suitableshallow angle relative to the longitudinal axis of wire frame 120.

Filter device 100 includes a cylindrical insert 115 having a socket 116that is suitably configured for attaching filter device 100 to a devicetether or shaft (similar to insert 715 in device 700, FIG. 13c ). Insert115 is attached to collar 122 of wire frame 120 (FIG. 14a ). Collar 122may have holes 129 suitable for receiving, for example, cotter pins tofasten insert 115 in position. FIG. 14b shows, for example, the relativeradial sizes of wire frame 120, insert 115 and socket 116.

The positioning of collar 122 along the longitudinal axis of wire frame120 may be suitably chosen with consideration to the exterior surfacetopography presented by deployed device 120 to atrial blood flow. Therecessed location of collar 122 may reduce or minimize the extension orprotrusion of insert 115 normal to the back plane of device 100. Atrialappendage implant devices with few or little back plane protuberancesmay be desirable as such devices are unlikely to impede or disrupt bloodflow through the atrium.

In preferred embodiments of either device 700 or 100, their respectivewire frame structures 720 or 120 are shaped so that annular portions oftheir proximal surfaces (closed end) are concave or dimpled toward thedistal end of the device (see, e.g., FIG. 13b and FIG. 14a ). Thisconcavity allows wire frame collar 722 (122) to be positioned along thelongitudinal axis of wire frame 720 (120) at or about the closed-endback plane (e.g., back plane 120 b, FIGS. 14a and 15a ). With the wirecollars so disposed, filter membrane 710 (110), which is held betweenthe collar 722 (122) and insert 715 (115), may be supported over theclosed end of wire frame 722 (122) in a substantially flat configuration(see e.g., FIG. 13a and FIG. 14a ). Further, inserts 715 and 115 mayhave suitably small axial dimensions so that they do not protrude fromor do not extend substantially beyond the devices' closed-end backplanes (120 b). Devices 700 or 100 of these preferred embodiments, whendeployed in an atrial appendage, present a relatively flat proximalsurface topography that does not protrude into the atrium orsignificantly disturb atrial blood flow past the appendage opening.

The concavity of portions of the back surface of the wire frames alsomay give portions of the wire frames an S-shape. These portions (e.g.,sections 723, FIG. 13a , sections 123, FIGS. 14a and 15a ) may serve asS-shaped resilient springs that push the cylindrical side portions ofthe wire frames radially outward to engage atrial appendage walls. Wireportions 123 c, for example, with reference to FIGS. 15c , form thechicken-wire mesh-like cylindrical sides portions of wire frame 120. Atone end each S-shaped wire section 123 is attached to collar 122. Theother end of each S-shaped wire section 123 is connected to wireportions 123 c. FIG. 15e shows an enlarged view of an exemplarymechanical transition from a S-shaped wire section 123 to distalchicken-wire mesh-like wire portions 123 c. S-shaped sections 123 maylie in radial planes that intersect each other along the longitudinalframe axis (FIG. 15g )

Filter devices 100 or 700 (or other expandable devices) may be implantedin a patient's atrial appendage using percutaneous catheterizationprocedures. The catheterization procedures involve first deploying anaccess system to position an access sheath through a patient's vascularsystem to the interior locations in the patient's heart, (e.g., to theatrial appendage). The access sheath provides a passageway through whichmedical instrumentation such as probes or implant devices are passedfrom outside the patient's body to interior locations in the heart.Independent delivery systems may be used to deliver the probes ordevices through the access sheath. The inventive delivery systems thatmay be used can be of one or more types (e.g., delivery system 200, 800or 800A).

FIGS. 8 and 9 show access system kit 500 which may be used to establisha passageway for device delivery to an atrial appendage through apatient's vasculature. Access system kit 500 includes access sheath 510,dilator 520, obturator 540, and Brochenbrough needle 530. Access sheath510 has a tubular structure. Access sheath 510 tubing may be made of anysuitable flexible materials. Access sheath 510 may, for example, be madefrom braided wire tubing having a plastic outer coat. In the example,the braided wire may be stainless steel and the plastic outer coat maybe any suitable plastic polymeric material such as urethane. The distalend or tip of the access sheath is made of curved tubing which can bestiffened or straightened as necessary during the insertion of theaccess sheath through the vasculature and across the cardiac septum. Thecurved shape of the access sheath tip may be designed to take intoaccount the anatomical geometry of the vasculature and the heart.

The diameter of the tubing used to fabricate access sheath 510 isselected to be sufficiently large to allow convenient passage of probesor tubular portions of the implant device delivery systems (e.g., FIG. 2delivery catheter tube 200) through it. An exemplary access sheath 510is made from French size 12 (4 mm diameter) tubing. Other French sizetubing (smaller or larger than French size 12) may be used as needed fordifferent sizes of probes or implant devices. Further, the interiorwalls of the tubing material may be lined with lubricious material suchas PTFE (e.g., Teflon®) for easier sliding passage of probes or implantdevice delivery systems through access sheath 510. The liner materialmay extend through the distal end of the tubing material to form a softdistal tip 512. The proximal end of the stainless tube is connected tovalve assembly with fluid seals acting against tubes or catheters thatmay be inserted into the access sheath to prevent the leakage of fluidsduring use. For example, a hemostasis valve assembly 514 is attached tothe proximal end of the sheath tube. Valve 514 may, for example, have aconventional hard plastic material shell construction with siliconematerial valve seals. Optional port 515 on the proximal end of accesssheath 510 provides fluid communication with access sheath 510 lumen. Astopcock valve, for example, a three-way valve 516, may be used tocontrol the flow of fluids through port 515.

Access system kit 500 components Brochenbrough needle 530, dilator 520,and obturator 540 may be conventional components suitably adapted to fitin access sheath 510 for use in conjunction with access sheath 510.Brochenbrough needle 530 is a hollow curved tube. Needle 530 may be madeof any suitable material such as a stainless steel tube. Valve 532 sealsthe proximal end of the tube. The distal end of the tube is sharpened toform a needle tip 532. Obturator 540 is made from a length of a suitablesolid wire having a blunt end 542. An exemplary obturator 540 is madefrom 14 mils diameter stainless steel wire. Obturator 540 is designed toslide through needle 520 with blunt end 542 extending out of needle tip532. In use, the extension of blunt end 542 through needle tip 532prevents needle tip 532 from causing inadvertent punctures ofsurrounding tissue or tubing. Dilator 520 is another curved hollow tubelike-structure that can fit in access sheath 510. Dilator 520 also, may,for example, be made with from stainless steel tubing. Dilator 520 isdesigned to fit through access sheath 510 over needle 530.

Access system kit 500 may be used in a transseptal catheterizationprocedure for implanting filter devices, for example, in a patient'sLAA. In such a catheterization procedure, access sheath 510, dilator520, and needle 530 may be conventionally prepared for introduction intoa patient's vascular system, for example, by flushing them with salinesolution to remove air from their lumen. A conventional short introducersheath or needle may be used to make a puncture opening, for example, inthe right femoral vein (or artery), through which Brochenbrough needle530 is introduced into the patient's vasculature. Alternatively, apuncture opening made by the sharpened needle tip 532 it self may beused to introduce needle 530 into the patient's vasculature.

Next, a length of conventional guide wire may be advanced through needle530 (or the introducer sheath) ahead of the needle tip into the femoralvein. The guide wire may, for example, be a standard 35 mils diametersteel wire. Access sheath 510 and dilator 520 are then advanced over theguide wire through the femoral vein into the right superior vena cava.Dilator tip 522 may extend out of access sheath 510, for example, byabout three quarters of an inch. Access sheath 510 and dilator 520 areadvanced sufficiently into the right atrium through the right superiorvena cava so that the dilator tip 522 is in close proximity to theatrial septum separating the right atrium from the left atrium. Next,the guide wire may be withdrawn and replaced by needle 530. Needle 530(with obturator 540 extending through it) is advanced through dilator520 so that needle tip 532 extends slightly out of dilator tip 522.Obturator 540 is then withdrawn to expose sharpened needle tip 532.

Next, needle 530, dilator 520, and access sheath 510 may be advanced,either sequentially or together, to puncture the septum, dilate thepuncture opening, and advance access sheath 510 through the dilatedseptal opening into the left atrium. Once access sheath is set up acrossthe septum, needle 530 and dilator 520 may be withdrawn.

A suitable septal puncture location may often be found within the thinwalled dimpled region of the atrial septum (fossa ovalis), which isbelow the position of the LAA on the left atrium (FIG. 1). Afteradvancing access sheath 510 through the dilated septal opening into theleft atrium, access sheath 510 tip is reoriented and redirected from thedirection of its entry into the left atrium toward the subject LAA. Thecurved shape of the distal access sheath 510 tip is advantageous inreorienting and redirecting it toward the subject atrial appendage. Thecurved shape may facilitate moving the access sheath through angles andin placing the access sheath in an orientation from which an implantdevice may be delivered directly into the subject atrial appendage. Thesheath tip curvatures may be suitably designed to ease access to atrialappendages, which are anatomically disposed in the remote or awkwardupper reaches of the corresponding atria. The suitable designedgeometrical curvatures of the sheath tip may be simple or compound.

In one embodiment, access sheath 510 tip has a simple geometriccurvature (e.g., J-shape). The length of the access sheath tubing may bechosen to have the ability to position distal end 512 in the atrialappendage. An exemplary access sheath 510 of this embodiment may have alength of about 33 inches (FIG. 9). The distal tip portion 510 c of thisexemplary sheath is a curved arc, which may have a radius of about a fewinches (e.g., 2 inches). Distal tip portion 510 c may be about onequarter of circle long. In another embodiment, access sheath 510 tip mayhave a geometrically compound curved shape. FIG. 10, 11 a and 11 b showan exemplary access sheath 510 in which the sheath tip has two adjoiningtip portions 510 a and 510 b. Portion 510 a may have a radius ofcurvature of about a few inches, and may like portion 510 c (FIG. 10) beabout one quarter of circle long. Adjoining portion 510 b may be a shortstub-like portion, which extends from portion 510 a and orients sheathexit opening (distal end 512) in a direction that is about normal oraway from the plane containing curved portion 510 a (FIGS. 11a and 11b).

With reference to and in continuation of the preceding description of atransseptal access procedure using access system kit 500, it will beunderstood that suitably curved access sheath 510 may be set up acrossthe septum so that its distal end 512 points toward the subject LAA.Access sheath 510 may be further advanced into the LAA itself. In someprocedures, access sheath 510 may be advanced so that distal end 512 isplaced deep inside the LAA. Once access sheath 510 is placed in suitableposition across the septum, it may be used as a passageway for deliveryof filter devices to the LAA from outside the patient's body. Suitabledelivery systems may be used to move the filter devices throughhemostatic valve assembly 514.

During the transseptal access sheath positioning or set-up proceduredescribed above, blood flow in needle 530 lumen may be sampled throughvalve 534, for example, to confirm the position of needle tip 532 ineither the right or the left atrium. Additionally or alternatively,fluids may be injected into the heart through access sheath 510 usingthrough port 515 for diagnostic or other purposes. For example, radioopaque dyes may be injected into the left atrial appendage to size theappendage to determine or select the appropriate or suitable implantdevice size. A selected device may be implanted in the LAA through thethrough the passage way formed by pre-positioned access sheath 510.

Inventive delivery systems may be used to implant the device throughaccess sheath 510. FIG. 2 and FIGS. 3a-3c , show, for example, adelivery system 200 that may be used to deliver and position implantdevices (e.g., filter device 700 and device 100) in a patient's LAAthrough access sheath 510. Delivery system 200 includes deliverycatheter tube 220 that distally extends into a tubular implant sheath230. The proximal end of delivery tube 220 is slidably connected to ahollow handle or manifold assembly 210. Delivery tube 220 may bepartially retractable into manifold assembly 210. A tether wire 410passes through hollow handle 210 and delivery tube 220 into implantsheath 230 (FIGS. 3a-3c ). The distal portions of tether wire 410 may beencased in a flexible material, for example, distal flex coil 420 whosediameter is selected to fit inside implant sheath 230. The distal end oftether wire 410 terminates in fixture 430 suitable for attaching animplant device (FIG. 3a ). Fixture 430 may, for example, be a threadedscrew, which can be screwed into threaded socket 716 to attach, forexample, filter device 700 (FIG. 13a ). The proximal end of tether wire410 is attached to a rotatable knob 260 mounted on handle 210. Rotatableknob 260 may be manually rotated to turn fixture 430.

The implant device selected for implantation in the patient is attachedto distal tether wire fixture 430, compressed or compacted to a narrowdiameter size and loaded in implant sheath 230. Implant devices havingthreaded sockets (e.g., device 700 insert 715, FIG. 13a ) may beattached (or detached) to tether wire 410 by turning rotatable knob 260.Handle or manifold assembly 210 may be fitted with a mechanical safetycap 280 to cover rotatable knob 260 to prevent inadvertent unthreadingor detachment of an attached device. To gain access to knob 260, anoperator must first remove safety cap 280. The attached device iscompressed in size (e.g. compressed device 700 a, FIG. 3b ) to fit inimplant sheath 230. The walls of implant sheath 230 restrain compresseddevice 700 a from expanding during device delivery. For deployment insitu, compressed device 700 a is expelled from implant sheath 230 from asuitable deployment position in or about the subject LAA.

Compressed device 700 a may be unconstrained or expelled from theimplant sheath 230 for deployment by retracting delivery tube 220 overtether wire 410 into handle 210. Delivery system 200 includes externalcontrol mechanisms, which may be activated to retract delivery tube 220over tether wire 410. In an embodiment of delivery system 200, theproximal end of delivery tube 220 is attached to reciprocating sheathactuator 240. Sheath actuator 240 may slide along handle or manifoldassembly 210 to partially retract delivery tube 220 into manifold 210 orto further extend delivery tube 220 from manifold 210. Additionally,manifold 210 may be fitted with an optional actuator lock 290 to preventinadvertent movement of sheath actuator 240. Movement of sheath actuator240, may be enabled only after actuator lock 290 must be removed.

Sheath actuator 240 may have suitable hemostatic fluid seals (e.g.,rubber seals 242, FIG. 5) acting against the surface of tether wire 410passing through handle 210. The fluid seals may prevent fluid leakagefrom delivery tube 220 as sheath actuator 240 is moved along handle 210over a length of tether wire 410. Sheath actuator 240 also may includean optional pipe fitting, for example, female luer fitting 245, in fluidcommunication with delivery tube 220 lumen. Fitting 245 may, forexample, be used to flush delivery tube 220 with saline solution priorto use to remove air from delivery tube 220 lumen. Fitting 245 also maybe used to sample blood or for infusion of drugs and other fluids intodelivery tube 220 during use.

In the device implantation procedure, delivery system 200 is insertedinto pre-positioned access sheath 510 through hemostasis valve assembly514. Delivery tube 220 is advanced through access sheath so that implantsheath 230 extends out of access sheath tip 512 toward the subject LAA.

The length of catheter delivery tube 220 (and that of tether wire 410)desired for a catheterization procedure may be chosen or determined byconsideration of length of the vascular pathway to the atrial appendage.Catheter delivery tube 220 lengths of about 80 cms. to 125 cms. may beappropriate for most adult catheterization procedures. Implant sheath230 may have a length sufficient to axially cover distal flex coil 420and the compressed implant device. The diameter of delivery cathetertube 220 and implant sheath 230 are kept small in consideration of thesize of typical vascular pathways and the flexibility required fordelivery catheter tube 220 and implant sheath 230 to traverse accesssheath 510.

In an exemplary delivery system 200, the inside diameter of deliverytube 220 may be about 45 mils. Implant sheath 230, which constrainsunexpanded filter devices, may have a larger diameter of about 90 milsto accommodate the larger diameter of an unexpanded filter device. (Itwill be understood that in practice a wide range delivery tube 220 andimplant sheath diameters may be used as appropriate). In the example,tether wire 410, which passes through delivery tube 220, has a diametersmaller than 45 mils so that it can easily slide through delivery tube220. An embodiment of tether wire 410 is made from a nitinol or othermetal wire having a diameter of about 35 mils over most of its length. Ametal wire of this diameter may be sufficiently stiff or rigid to allowfor its smooth passage through delivery tube 220, and for mechanicallycoupling the motion of knob 260 to that of a filter device attached tothe other end of tether wire 410. However, a distal section 432 oftether wire 410 of this embodiment may have a reduced diameter of about10 mils (FIG. 3a ). The diameter decreases gradually from a proximalsection 436 diameter (35 mils) to a distal section 432 diameter (10mils) over a taper section 434. Taper section 434 may have a length, forexample, of about 1 to 2 cms.

This manner of wire diameter reduction lessens the coupling stiffnessbetween tether wire 410 and a filter device attached to fixture 430. Thelessening of coupling stiffness may allow the filter device deployed inan atrial appendage to be detached or released from device tether 410,without significant recoil. Recoilless release or release with minimumrecoil is desirable as recoil may cause the deployed device to tip ordislodge from its pre-release position in the atrial appendage. Thereduced coupling stiffness also allows the attached filter device todeploy in its natural unbiased state in the atrial appendage while stillattached to the tether wire. These features may be advantageously usedto assess the suitability of an implant deployment prior to detachmentof tether wire 410. The deployed device may be viewed in its unbiasedstate while it is still attached to tether wire 410. An improperly orunsuitably deployed device may be retrieved, for example, by extendingimplant sheath 230 over still-attached tether wire 410 to recapture thedevice or by pulling the device back into implant sheath 230 withstill-attached tether wire 410.

FIG. 3c shows a distal section of tether wire 410 of the aforementionedembodiment. FIG. 3c also shows an expanded filter device (e.g., device700) attached to the distal end of tether wire 410. Portion 410 brepresents the section of tether wire 410 with the wire diameter reducedto about 10 mils. Portion 410 b is encased in distal flex coil 420. Thelatter may be made of coiled or molded plastic elastomer material. Flexcoil 420 is designed to have a diameter to occupy the luminal spacebetween the inner walls of implant sheath 230 and tether wire portion410 b. By taking up the dead space in implant sheath 230, distal flexcoil 420 may prevent reduced diameter wire tether portion 410 b frombuckling when tether wire 410 is moved relative to implant sheath 230.

In some cases of the device implantation procedure using delivery system200, access sheath 510 may be pre-positioned such that sheath tip 512 isitself advanced into the subject atrial appendage. In other cases,access sheath 510 may be pre-positioned such that sheath tip 512 isoutside or at the atrial appendage opening. In either instance, implantsheath 230 may be advanced out of access sheath tip 512, for example, tothe back of the subject LAA, in preparation for device deployment. Thenaccess sheath 510 may be partially retracted to pull access sheath tip512 clear of the subject atrial appendage (if necessary) for devicedeployment. Access sheath 510 may be pulled back a sufficient distanceso that tip 512 is back at the opening of the atrial appendage or iscompletely out of the atrial appendage. Next, the compressed implantdevice contained in the implant sheath 230 may be deployed in the atrialappendage by retracting implant sheath 230 to uncover compressed implantdevice 700 a. Implant sheath 230 may be retracted over tether wire bysliding sheath actuator 240 backward over manifold 210 to retractdelivery tube 210 into manifold 210 (e.g., FIGS. 2 and 5).

As implant sheath 230 is retracted, the implant device (e.g., device700) expands in situ to its natural size. As filter device 700 expands,filter membrane 710 extends across the atrial appendage ostium tointercept blood flow. In the expanded device, cylindrical side portionsof wire frame 720 press radially outward in opposition to the interiorwalls of the atrial appendage. Additionally, wire frame 720 featuressuch as barbs 728 engage atrial appendage wall tissue. The outwardcontact pressures, which may be resisted by atrial wall muscle tissue,and the engagement of appendage wall tissue by barbs 728, secure theexpanded device in an implant position. After filter device 700 issuitably expanded in situ, it may be released or detached from tetherwire 410. To release filter device 700, first, safety cap 280 is removedto gain access to release knob 260. Next, release knob 260 may be turnedor rotated to unscrew fixture 430 from socket 715 to release filterdevice 700 from tether wire 410.

It will be understood that suitable external imaging techniques may beused during the catheterization procedure to monitor the in vivoposition of the components of the access system and the device deliverysystem. These techniques may include but are not limited to techniquessuch as radiography or fluoroscopy, echocardiography includingtransesophageal echocardiography, and ultrasound. It will also beunderstood that the various components of the device delivery system andthe access system may include materials having suitable properties(e.g., radio-opacity) that make it possible to monitor the in-vivocomponent positions using the appropriate external imaging techniques.

For some assessment or imaging techniques, port 514 on access sheath 510may be used to inject fluids into the heart including, for example,radio opaque dyes, at any suitable times in the procedure including whendelivery catheter tube 210 extends through access sheath 510. Indelivery system 200, delivery tube 220 lumen may be used to transmitfluids. For such use, flex coil portions in which distal portions oftether wire 410 are encased may include flush ports to allow fluids tobe injected into the heart or atrial appendage through delivery tube 220lumen. FIGS. 4a-4b show a coil 620, which may be used to encase thedistal narrow diameter portions of tether wire 410. Coil 620 may be madeof soft polymeric materials (including, for example, thermoplasticelectrometric resins that may be sold commercially under the trade namePEBAX®). The outer diameter of coil 620 (like that of coil 420) may beabout the same as the inner diameter of implant sheath 230. Coil 620includes axial lumen 622 that leads to flush ports 624 near the distalend of coil 620. An exemplary lumen diameter may be about 75 mils.Proximal end portions 628 of coil 620 may be designed for mechanicalconnection with delivery tube 220. For example, proximal end portions628 may be tapered to provide interference fit in delivery tube 220(FIGS. 4a and 4b , delivery tube 220 not shown). Tether wire 410, whichmay have a diameter of about 35 mils or less, passes through deliverytube 220 and through coil 620 so that device-attachment fixture 430extends out of coil 620. A mechanical restraint, for example, acylindrical plug or stop 626 that fits in axial lumen 622, may be usedto hold coil 620 in position over tether wire 410. Cylindrical plug 626may be glued to tether wire 410 with suitable adhesives or epoxymaterial 627 (FIG. 4b inset). Fluid connectivity around plug 626 betweendelivery tube 220 lumen and axial lumen 622 may be provided by groovesand holes 629 fashioned in proximal end portions 628 of coil 620. Fluidsthat are injected into delivery tube 220 lumen (e.g., through fitting245, FIG. 2) may pass through holes 629 into lumen 622 and aredischarged from flush ports 624. This fluid pathway may, for example, beused to inject radio opaque dyes into atrial appendages around implantdevices that are still attached tether wire 410. Such radio opaque dyeinjection may be advantageous in assessing the positioning of expelledor deployed devices in the atrial appendage before tether wire 410 isdetached. If the position of the expelled device is not appropriate,sheath actuator 240 may be activated to slide implant sheath 230 forwardover tether wire 410 to recapture the device for repositioning orwithdrawal as desired.

In other embodiments of the device delivery system, tether wire 410itself may be used as the primary means to control movement of theattached implant device in and out of implant sheath 230. FIGS. 6 and 7show, for example, delivery system 800 in which the movement of tetherwire 410 through delivery catheter tube 220 controls the movement of theattached implant device in or out of implant sheath 230 (implant devicenot shown). For brevity, the description of delivery system 800 hereinis generally limited only to some of its features that may differsignificantly from the corresponding structures or features of deliverysystem 200.

Device delivery system 800 includes delivery catheter tube 220 thatdistally extends into a tubular implant sheath 230. The to be implanteddevice is attached to tether wire 410 and is contained in implant sheath230. A radial compression valve assembly 810 is mounted or connected tothe proximal end of delivery catheter tube 220. Radial compression valveassembly 810 may, for example, be a large bore Touhy Borst valveassembly. The side-arm or Y-arm 814 of the Touhy Borst valve assemblyallows intermittent or continuous flushing and contrast injection, andalso allows for continuous blood monitoring through delivery tube 220lumen. A multi-way stopcock 816 may be attached to Y-arm 814 to regulateor control the flow of fluids through Y-arm 814.

Tether wire 410 slidably passes through valve assembly 810 and deliverytube 220 into implant sheath 230. Touhy Borst valve assembly 810 sealspermit unimpeded translational or rotational movement of tether wire410, whose proximal end is attached to a control handle or knob 820. Inuse knob 820 may be manipulated to translate or rotate tether wire 410as necessary at appropriate steps in the device implantation procedure.For example, to insert or deploy an attached device in the subjectatrial appendage, tether wire 410 may be translated forward throughhemostatis valve assembly 810 to push the attached device out of implantsheath 230. A rotational motion of tether wire 410 may be used tounthread and detach the deployed device.

Proximal portions of tether wire 410 leading to control knob 820optionally may be clad by stiffening material or tube 822. Stiffeningtube 822 may provide mechanical rigidity for transmitting, for example,control knob 820 rotation or torque to the threaded fixture 430 over thelength of tether wire 410.

It will be understood that the various components of device deliverysystem 800 (e.g., knob 820, valve assembly 810, delivery tube 220,stopcock 816, etc.) may be mutually attached or connected using suitableadhesives, glues, and epoxy materials, and/or conventional fittings.Some or all sections of deliver system 800 may be fabricated usingoff-the-shelf components or alternatively may be fabricated as singlepieces using techniques such as injection molding. For example,pipefitting or locking nut 812 may be used to connect delivery tube 220to threaded portions of valve assembly 810.

Delivery system 800 and access sheath 510 may optionally includefittings or other coupling mechanisms, which allow them to bemechanically coupled. The coupling mechanism may, for example, be amanually adjustable mechanical lock. The coupling mechanisms may, forexample, include threaded nut connectors, bayonet connectors, pinconnectors, screwed flanges, or any other suitable connectors which canbe used to lock the access sheath and the delivery system together. Thesuitable connectors may include pipefittings such as leur fittings.

FIGS. 12a-12d show, for example, access sheath 510 and delivery system800 with lock fittings or adapters 550 a and 850 a, respectively.Fitting 550 a may, for example, be a socket or female adapter fashionedin hemostasis valve 514 at the distal hub of access sheath 510. Fitting850 a may be a pin or male adapter disposed over delivery tube 220adjacent to valve assembly 810. Fittings 550 a and 850 a may havematching structures and dimensions that allow access sheath 510 anddelivery system 800 to be mechanically coupled or joined together.Matching lock fittings 550 a and 850 a may be designed to be capable ofready and repeated physical engagement or disengagement (with or withoutthe use of a tool). Access sheath 510 and delivery system 800 may bemoved together when joined or combined by the coupling mechanism, orindependently when the coupling mechanism is inactive. Mechanicallycoupling delivery system 800 to access sheath 510 may be advantageous inobtaining a stable passageway for moving implant devices attached to atether wire. The mechanical coupling also may be useful inpredetermining and fixing the relative positions of implant sheath 230and access sheath tip 512, and in moving the two together.

FIGS. 12a and 12b show delivery system 800 and access sheath 510 in use,for example, during a catheterization procedure, with delivery cathetertube 220 inserted in access sheath 510 through hemostasis valve 514 withmatched luer fittings 850 a and 550 a separated and disconnected. Inthis state both delivery catheter tube 220 and access sheath 510 can bemoved independently. In routine operation, delivery catheter tube 220may be advanced through access sheath 510 until fitting 850 a locks infitting 550 a. When locked together, the distal end of implant sheath230 may, for example, be flush with access sheath tip 512 (or atseparation distance which is predetermined by the positioning of fitting850 a along the length of delivery tube 220).

FIGS. 12c and 12d show delivery system 800 and access sheath 510 withfittings 850 a and 550 a locked together. In the locked state bothdelivery catheter tube 200 and access sheath 510 move together in amechanically joined or combined fashion. An implant device (e.g., device100) may be deployed, for example, in the subject LAA, by retracting thedelivery tube/access sheath combination over wire 410 to unsheathe theself-expanding implant device (FIG. 3, LAA not shown).

Other types of locks and/or valve assemblies may be incorporated inaccess system sheath 510 and delivery system tube 800. Theconfigurations of these other types of locks and valves may providedifferent or additional operational features. For example, FIGS. 16a-18bshow another access system sheath 510A and another delivery system 800A.Again for brevity, the description of delivery systems 800A and accesssystem 510A herein is generally limited only to those features that maydiffer significantly from the corresponding structures or features ofdelivery systems 200 and 800 and access system 510.

Access system sheath 510A, shown in FIGS. 16a and 16b , may have aradial compression valve assembly 514A at its proximal hub. Radialcompression valve assembly 514A may have any suitable conventionaldesign. Valve 514A may, for example, have a Touhy Borst design with acylindrical body 514 c that houses a suitable radial shaft seal (notshown). The shaft seal may, for example, be made from a cylinder or ringof silicone material. A knurled knob 514 k, which rotates on threadedportions of cylinder body 514 c, may be used to controllably compressthe shaft seal against a passing shaft or tube (e.g., delivery tube220). The use of rotary valve 514A having an adjustable shaft seal maybe advantageous in controlling back bleeding during the manipulation ofthe delivery tube or other instrumentation (e.g., guide wires) throughaccess sheath 510A.

Access system sheath 510A may be used with a suitably adapted deliverysystem, for example, delivery system 800A shown in FIGS. 17a-17c .Delivery system 800A and access system sheath 510 may be locked togetherusing suitable snap-on locking arrangements. The locking arrangement mayrestrict the relative translation and/or rotation of the two systems. Asnap-on locking arrangement may include, for example, a C-shaped clip852 that is disposed on the distal ends of delivery system valveassembly 810 (FIG. 17a ). Further, cylinder body 514 c of valve 514A atthe distal end of access sheath 510 may be provided with suitabledetents, grooves, holes or rings, to receive and hold the tips ofC-shaped clip 852. For example, ring 552 on cylinder body 514C may bedesigned to receive and slidably hold the tips of C-shaped clip 852.Ring 552 may be immovably fixed on cylinder body 514 c , oralternatively ring 552 may be rotatably mounted on cylinder body 514 c.Like luer-type lock fittings 550 a and 850 a (FIGS. 12a-12b ), C-shapedclip 852 may be designed to be capable of ready and repeated physicalengagement or disengagement with ring 552.

In operation, delivery system 800A may be mechanically locked withaccess system 510A by suitably advancing delivery system 800A so thattips of C-shaped clip 852 catch or snap behind ring 552. The exemplaryC-shape locking mechanism may mechanically couple delivery system 800Ato access sheath 510A to obtain a stable passageway for moving implantdevices attached to a tether wire, while allowing desirable rotationalmotion of delivery tube 220 and delivery system 800A. For example,C-shape clip 852 when locked prevents the linear or translation movementof delivery system 800A relative to access system sheath 510A. Therotational motion of delivery tube 220 passing through rotary valve 514Amay remain unconstrained as the tips of C-shape clip 852 may slid aroundring 552 (or alternatively ring 552 may rotate around cylindrical body514 c). Further, open spacing 852 a that is delimited by C-shape clip852 provides operator access to knob 514 k. This access may beadvantageously used to adjust knob 514 k, for example, to control backbleeding during the device implantation or other procedures.

FIGS. 18a and 18b show delivery system 800A and access sheath 510A inuse, for example, during a catheterization procedure, with deliverycatheter tube 220 (not seen) inserted in access sheath 510A throughrotary valve 514A with C-shape clip 852 locked on cylindrical body 514c. In the locked state both delivery system 800A and access sheath 510Amay be moved together linearly. Delivery catheter tube 220 and deliverysystem 800A may be rotated as necessary or advantageous, for example, toorient or position the implant device (e.g., device 100) attached to thedistal end of tether wire 410. Access to knurled knob 514 k throughspacing 852 a allows the operator to adjust the radial or shaft seal ofvalve 514 around catheter tube 220 to allow free rotation and/or controlback bleeding.

The design of systems 800A and 510 may incorporate other optionalfeatures involving operator use of the systems. For example, FIGS.17a-18b show an additional locking clip 890 mounted on tether wirecasing 822. Clip 890 may have a suitable releasable or detachablestructure. Clip 890 may, for example, be a plastic flag or tab which isreleasable, mounted in a slot running along casing 822 tube. Clip 290Aacts as a stop against the distal end of Touhy Borst valve or manifoldassembly 810. Clip 890 may be mounted at suitable distance along wirecasing 822 to limit the length of tether wire 410 that can be insertedin delivery tube 220. By limiting the inserted length of tether wire410, clip 890 may prevent premature expulsion and deployment of theimplant device attached to the end of tether wire 410. In use, clip 890may be removed or released by an operator after combination of accesssheath 510A/delivery tube 800A has been suitably placed (e.g., in asubject LAA) for device deployment. Then the operator may extendadditional lengths of tether wire 410 through delivery tube 220 to pushthe tethered device out of the constraining implant sheath 230 fordevice deployment. The deployed device may be released by turningcontrol knob 820.

Delivery system 800A and tether wire 410 may include suitable featuresto prevent inadvertent release of the device attached to the distal endof tether wire 410. For example, proximal hub 832 of Touhy Borstassembly 810 (e.g., at the end opposite from clip 852) may include aD-shaped lumen or keyway for the passage of tether wire 410/casing 822.FIG. 19c shows, for example, D-shape keyway 815 that is located to theleft of washer 819 and silicone seal 817. Portions or lengths of tetherwire 410/casing 822 may have a suitable cross-section that allows it toslide through keyway 815 but which prevent its rotation. For example,casing length 822D may have a D-shaped cross-section that allows slidingpassage of tether wire 410/casing 822 through keyway 815 but one thatprevents rotation. Further, casing 822 at its extreme distal endportions abutting knob 820 may have a suitable cross-section that canrotate through the keyway 815. For example, short casing length 822R mayhave a round cross-section. In use, tether wire 410 is restrained fromturning while casing length 822D is in keyway 815, which, may correspondto when the attached device is within implant sheath 230. Tether wire410 can be turned only when knob 820 is pushed up against connector 812so that round cross-section casing length 822R is within keyway 815. Thelength of tether wire 410 may be designed so when knob 820 is pushed upagainst connector 812 the implant device is pushed out of implant sheath230. Thus the device may be detached by unscrewing tether wire 410 onlyafter it has been has been expelled from implant sheath 230 by pushingknob 820 up against up against connector 812. The operator may, forexample, release the deployed device by turning knob 820.

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. It will be understood that terms like “distal” and“proximal”, “left” and “right”, and other directional or orientationalterms are used herein only for convenience, and that no fixed orabsolute orientations are intended by the use of these terms. 1. A bloodfiltration system for filtering blood flow from an atrial appendage,comprising: a filter device that is configured for deployment in theatrial appendage to intercept blood flow, wherein the filter device hasan elastic structure that expands to its natural size from a compressedstate when the device is unconstrained; a tubular access sheath forestablishing a percutaneous pathway to the atrial appendage; and adelivery instrument for delivering the device through a lumen of theaccess sheath and for deploying the delivered device in the atrialappendage, wherein the delivery instrument includes: a delivery tube;and a movable tether that passes through the delivery tube, and that isreleasably attached to the device, wherein the tether providesmechanical control over the delivery and deployment of the device, andwherein the access sheath and the delivery tube comprise releasablelocks for controlling the relative movement of the two.

1. A medical device configured for implantation in a left atrialappendage, the medical device comprising: a cylindrical supportstructure having a collapsed diameter and an expanded diameter, a distalend, a closed proximal end, and a proximal hub; a membrane covering theexterior of the closed proximal end of the cylindrical supportstructure, wherein the membrane defines a radial extent having adiameter greater than the expanded diameter of the cylindrical supportstructure; and a plurality of hooks attached to the cylindrical supportstructure distal of the membrane, each hook of the plurality of hookshas a radial extent greater than the expanded diameter of thecylindrical support structure, wherein a tip of each hook of theplurality of hooks is proximally directed and is adapted to engagetissue thereby tending to resist withdrawal of the cylindrical supportstructure when the medical device is implanted in a left atrialappendage.
 2. The medical device of claim 1, wherein the cylindricalsupport structure comprises a plurality of wires.
 3. The medical deviceof claim 2, wherein the plurality of wires are braided wires.
 4. Themedical device of claim 3, wherein the braided wires are shape memorywires.
 5. The medical device of claim 4, wherein the shape memory wiresare nitinol wires.
 6. The medical device of claim 1, wherein thecylindrical support structure is configured and adapted to transitionfrom a radially compact delivery configuration to a radially expandeddeployed configuration.
 7. The medical device of claim 6, wherein thecylindrical support structure is a self-expanding cylindrical supportstructure.
 8. The medical device of claim 6, wherein the cylindricalsupport structure is a balloon expandable cylindrical support structure.9. The medical device of claim 6, wherein the cylindrical supportstructure is a mechanically expandable cylindrical support structure.10. The medical device of claim 1, wherein the distal end of thecylindrical support structure is open.
 11. The medical device of claim1, wherein the cylindrical support structure comprises a plurality offenestrations.
 12. The medical device of claim 1, wherein a portion ofthe membrane adjacent the closed proximal end of the cylindrical supportstructure is a planar portion.
 13. The medical device of claim 12,wherein the planar portion of the membrane is perpendicular to alongitudinal axis of the cylindrical support structure.
 14. The medicaldevice of claim 1, wherein the proximal hub extends proximally from themembrane.
 15. The medical device of claim 14, wherein the proximal hubextends from the membrane in a perpendicular direction.
 16. The medicaldevice of claim 1, wherein the proximal hub is configured and adapted toreleasably engage a distal end of a delivery device.
 17. The medicaldevice of claim 16, wherein the adaptation to releasably engage a distalend of a delivery device comprises a threaded bore which mates with athreaded distal end of the delivery device.
 18. The medical device ofclaim 1, wherein the cylindrical support structure is a one-piece frame.19. The medical device of claim 1, wherein the membrane is ablood-permeable membrane.
 20. The medical device of claim 19, whereinthe blood-permeable membrane includes openings sized and adapted tofilter harmful-sized emboli from a blood flow between the left atrialappendage and a left atrium.